> What is the total prevalence of all conditions medically recognized as intersex?

Not all biological variation is classified as intersex.

> What is that even supposed to mean?

You can change a lot of your 'secondary sex characteristics' intentionally. This is much easier than removing a limb, and even easier than adding a limb.

> Not all biological variation is classified as intersex.

Okay, but other biological variation is clearly not relevant to the discussion.